Smoke alarms we install
There are two kinds of smoke alarm in NSW homes:
- Battery-only alarms, which you can stick up yourself and are allowed in existing homes.
- Hardwired (240 V) alarms, connected to the house wiring with a battery backup. These need a licensed electrician to install, repair or replace.
We install and replace hardwired alarms, and interconnect them so that when one goes off, they all go off. That matters in a bigger home or one with the bedrooms down a hallway, where you might not hear an alarm at the other end with the doors shut.
What NSW law requires
Smoke alarms aren't part of the electrical Wiring Rules. They're required by planning and building law and, for rentals, by tenancy law. In short:
- Every home where people sleep needs them. That includes owner-occupied homes, rentals, caravans and moveable dwellings. The requirement sits in the Environmental Planning and Assessment (Development Certification and Fire Safety) Regulation 2021, and has applied since 1 May 2006.
- The legal minimum is one working alarm on each level of the home.
- Alarms must comply with AS 3786.
- Existing homes can use battery alarms. NSW does not require an alarm in every bedroom, or hardwired interconnected alarms, in existing homes. Those bedroom-and-interconnection rules you may have read about are Queensland law.
- New homes and relevant building work are different. Under the National Construction Code 2022 Housing Provisions (Part 9.5), alarms in a new house must be connected to mains power where it's supplied, and interconnected where there's more than one. NCC 2022 is still the version in force in NSW. NSW adopts NCC 2025 on 1 May 2027.
Fire and Rescue NSW has a plain-English summary on its smoke alarm page. Our guide to smoke alarm rules in NSW goes into more detail.
Going beyond the minimum
The law sets a floor, not a target. Fire and Rescue NSW recommends:
- interconnected alarms in every bedroom, living area, hallway and stairway, and the garage
- photoelectric alarms
- replacing alarms at least every 10 years
If your alarms are yellowing, chirping, or you can't remember when they went in, check the date on the back. If it's past 10 years, or there's no date, they're due.
For landlords and property managers
Rentals have their own rules under the Residential Tenancies Act 2010 and the Residential Tenancies Regulation 2019. The landlord must:
- keep alarms in working order, and not remove or disable them
- check them every year
- replace removable batteries every year (lithium batteries: the period the manufacturer specifies)
- replace alarms within 10 years of manufacture, or sooner if the manufacturer says so
- repair or replace a faulty alarm within 2 business days of finding out, including a flat removable battery
- use a licensed electrician to repair or replace a hardwired alarm
Tenants may replace removable batteries only, and must not touch hardwired alarms. If the landlord doesn't act within 2 business days, the tenant can arrange a licensed electrician and be reimbursed within 7 days (this doesn't apply to social housing). Notice periods are at least 2 business days to inspect an alarm and 1 hour to repair or replace one. The NSW Government rental smoke alarm page has the full detail, and we cover it in smoke alarms in rental properties.
Property managers can send several addresses through at once. While we're there, we can also check the safety switch, which the condition report records too. See landlord electrical obligations in NSW.
How Nelson does it
- Checks what's there now: type, age, location and whether they're hardwired.
- Recommends where alarms should go, starting with the legal minimum and then what Fire and Rescue NSW recommends, and gives you a written price.
- Installs AS 3786 alarms. Hardwired alarms are connected to mains power with battery backup, and interconnected where you want them to be or the job requires it.
- Tests each alarm, and for interconnected systems checks that setting one off sets them all off.
- Lodges a Certificate of Compliance for Electrical Work (CCEW) for the wiring, through the Building Commission NSW eCert portal, with a copy emailed to you.
For new homes and extensions we fit alarms as part of the new build or renovation wiring, to the NCC requirements.
How it's priced
It depends on how many alarms, whether there's existing wiring to use, and how easy the roof space is to get through. Older homes with a low-pitched roof take longer than a new build with good access. Call or send the job through for a written quote. Travel is free close to Wagga and charged further out, and Nelson includes it in your quote.
Common questions
Do smoke alarms have to be hardwired in NSW?
Not in an existing home. The minimum is one working AS 3786 alarm per level, and battery alarms are allowed. New homes and relevant building work under the NCC need mains-powered, interconnected alarms.
Can I replace a hardwired smoke alarm myself?
No. Hardwired alarms are connected to the house wiring, and DIY electrical work is illegal in NSW. You can change the battery in a battery-only alarm. In a rental, hardwired alarms must be repaired or replaced by a licensed electrician.
How often should smoke alarms be replaced?
Fire and Rescue NSW advises at least every 10 years. In rentals, the law says within 10 years of manufacture, or sooner if the manufacturer specifies.
Do I need a smoke alarm in every bedroom in NSW?
The NSW legal minimum is one per level. Fire and Rescue NSW recommends going further, with interconnected alarms in every bedroom, living area, hallway and stairway, and the garage.
Which type of smoke alarm is best?
Fire and Rescue NSW recommends photoelectric alarms. Whatever you choose must comply with AS 3786.